Slide fastener having a filling core

ABSTRACT

A slide fastener is provided with a reinforcing core or filler extending through a helical structure of a continuous row of fastener elements for stabilizing the position of the latter when sewn onto a carrier tape. The core or filler is a tubular structure designed to flexibly yield itself and fit snugly into the coil of each element.

United States Patent 191 Takamatsu July 30, 1974 SLIDE FASTENER HAVING A FILLING [56] References Cited CORE v UNITED STATES PATENTS [75] Inventor; Ikuno Takamatsu, Uozu, Japan 3,783,476 1/1974 Frohlich 24/205.l6 C 73 Assignee: Yoshida Kogyo Kabushiki Kaisha, FOREIGN PATENTS 0R APPLICATIONS Tokyo, Japan 1,177,727 1/1970 Great Britain 24/205.1 c

[22] plied: 1973 Primary Examiner-Bernard A. Gelak [21] Appl. No.: 411,223 v I 5 7] ABSTRACT [30 Foreign Application p i t A slide fasteneris provided with a reinforcing core or NOV 6 972 M an 47428131 filler extending through a helical structure of a continp 7 uous row of fastener elements for stabilizing the posi- [52] U 8 Cl 24/205 1 C 24/205 1 tion of the latter when sewn onto a carrier tape. The 5 l] A44!) I12 core or filler is a tubular structure designed to flexibly [58] yield itself an fit g y into the Coil 'Ofeach element Field of samba/205.1 c, 205.13 "c, 205 16 4 Claims, 2 Drawing Figures 1 SLIDE FASTENER HAVING A FILLING CORE BACKGROUND OF THE INVENTION Such core or filler is made usually of fibrous or plastic materials and has a solid cross section either circular or square.

Known slide fasteners employing such reinforcing cores have met with the difficulties that the core when sewn together with the fastener elements to the carrier tape fails to yield itself to the inner peripheral contour of the fastener elements having an oval or egg-shaped cross section, with the results that there are produced irregular gaps between the core and-the leg portions and connecting portions of the coil elements. In other words, it has been difficult to hold the core in intimate contact uniformly with the inner periphery of each loop in a continuous coil fastener element row and in straight alignment with the longitudinal axis of the latter. Therefore, the conventional core, when sewn together with the row of fastener elements or otherwise subjected to pressure load, would serve adversely to cause objectionable deformation of the fastener elements and disturb the loop to loop spacing or pitch in the fastener element row. Sometimes, under the influence of external pressure the core makes a serpentine deflection such that the strength of coupling engagement between each loop of element differs throughout the length of the row of fastener elements and furthermore, the slider movement thereon is rendered extremely heavy at one place and conversely light at another.

SUMMARY OF THE INVENTION Whereas, it is an object of the inventionto provide improvements in slide fasteners of the type described whereby the aforesaid various difficulties of the conventional fasteners can be eliminated, such improvements being specifically directedto the physical .structure of a reinforcing corev to be employed for a helical coil type of fastener elements.

The above object together with other features of the invention will be apparent from the following description taken in conjunction with the accompanying drawings which illustrates by way of example a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of a segment of a slide fasteneraccording to the invention; and

FIG. 2 is a'transverse cross-sectional view taken @1005 the line IIII of FIGI l.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is shown a slide fastener whiehee-mprises a pair. of oppositely disposed carrier tapes 11,12 each carrying along one longitudinal inner edge a row of continuous fastener elements E formed into a helical coil structure having successive loops E En interengageable with those on the opposite tape. Each loop is cross-sectionally egg-shaped as seen in FIG. 2 and consists of a coupling head portion Ea, leg portions Eb and a connecting portion Ec as is usual with any known coil fastener element.

Extending longitudinally through the row of coil elements E is a reinforcing core 13 which in accordance with the invention has a tubular configuration with a hollow space 14 extending through its entire length. The reinforcing core 13 which constitutes an important feature of the invention .may preferably be made of fibrous yarns knitted into a tubular. form. Such knitted core may be further treated suitably with a synthetic resin. Alternatively, the core 13 may be formed by extrusion of a plastic material into a tubular structure.

Any other alternatives may be considered provided that they are hollow and restorable in resiliency under conditions in which the fastener is used.

The advantage of the hollow core 13 according to the invention is that when inserted in the successive loops E En and sewn together therewith to the respective carrier tape 11,(12) as by two-thread chain stitches S as shown, the core 13 can be brought into intimate contact with the internal peripheral surfaces of each loop including the leg portions'Eb and connecting pot.- tions Ec but of course excluding the coupling head portion Ea lest the core 13 should interfere with the space in which adjacent loops engage with each other. The core 13 being hollow and hence resilient can readily yield itself at any given point in response to the sewing pressure or other external load and assumes a crosssectional shape corresponding to the internal space of each loop defined by the leg portions Eb and connecting portions Be. This takes place without imparting stresses to the fastener elements E which would otherwise result in deformed elements or disturbed element.

pitches.

The reinforcing core 13 according to the invention will thus serve its purpose of retaining the rows of fastener elements-E stably in proper position on the carrier tapes 11,12, enhancing the strength of coupling engagement of the elements E uniformly throughout the length of the fastener, and further facilitating the smooth reciprocal movement of the slider along the rows of elements E.

What is claimed is:

l. A slide fastener comprising a pair of oppositely disposed carrier tapes, a row of fastener elements formed into a continuous helical coil structure and secured to each of said'tapes, each element having a coupling head portion, leg portions and a connecting portion and a reinforcing core of a hollow tubular structure extending longitudinally through said row of elements in intimate contact with the internal peripheral surfaces of said leg portions and connecting portions of each element. v

2. A slide fastener as defined in claim 1 wherein said core is made of fibrous yarns knitted into a tubular form.

3. A slide'fastener as defined in claim 1 wherein said core is extruded of a plastic material into a tubular form. t

4. A slide fastener as defined in claim 2 wherein said core is further treated with a synthetic resin,

. =1 =t= at is at 

1. A slide fastener comprising a pair of oppositely disposed carrier tapes, a row of fastener elements formed into a continuous helical coil structure and secured to each of said tapes, each element having a coupling head portion, leg portions and a connecting portion and a reinforcing core of a hollow tubular structure extending longitudinally through said row of elements in intimate contact with the internal peripheral surfaces of said leg portions and connecting portions of each element.
 2. A slide fastener as defined in claim 1 wherein said core is made of fibrous yarns knitted into a tubular form.
 3. A slide fastener as defined in claim 1 wherein said core is extruded of a plastic material into a tubular form.
 4. A slide fastener as defined in claim 2 wherein said core is further treated with a synthetic resin. 